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cotecha
Member
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# Posted: 21 Aug 2014 03:31pm
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Hello everyone,
We are building a small cabin and are not sure how to build our screened in porch. it is a one floor cabin up on piers 8 feet high. Not sure what type of roof it should be. the size will be approx. 10 feet depth and 16 feet wide.
any suggestions.
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LoonWhisperer
Member
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# Posted: 21 Aug 2014 05:41pm
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Tagged for interest. We want to add one as well.
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bldginsp
Member
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# Posted: 21 Aug 2014 06:12pm
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Do you get much snow?
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cotecha
Member
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# Posted: 21 Aug 2014 06:30pm
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yes, quite a bit actually and cold weather.
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bldginsp
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# Posted: 21 Aug 2014 06:35pm - Edited by: bldginsp
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Then I think you need to make a ridged gable to shed the snow. If you make a shed roof sloping down from the front wall, if it was steep enough to shed snow it would be too low. If it had little slope it would not shed snow and might collapse.
One possibility would be to extend the existing roof out 10 feet, or build a second roof about 18 inches below the first. Any way you do it, 160 square feet is enough to take a fair snow load so you should look closely at footing, beam, and rafter sizing.
But a low slope shed roof can work so long as it is designed to hold the snow load, which would call for some expense with concrete footings, wider rafters, etc.
Don't locate your door where the roof will dump piles of snow.
Hope this makes sense.
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cotecha
Member
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# Posted: 21 Aug 2014 07:00pm
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thanks for the info. It does make sense.
We are thinking of building a shed roof sloping down with a pitch 4/12, and attaching it 40 inches higher on the gable. Is that doable?
We will have 3-4 metal piers at the front on bedrock or it could be clay. we will find out next week.
what should be the ideal pitch for the shed roof sloping down.
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cotecha
Member
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# Posted: 21 Aug 2014 07:16pm
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Thank you so much for the info bldinsp. if we chose to build the second roof about 18 inches below the first, i guess we would need more piers? how many ?
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bldginsp
Member
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# Posted: 21 Aug 2014 07:51pm - Edited by: bldginsp
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Ideal pitch to shed snow is at least 8 in 12.
The number of piers depends on your design. The fewer piers, the longer span on your beams. So, you spend more on beams and less on piers, or vice versa, generally speaking.
Bedrock is ideal to locate any footing onto, clay is the worst. If you can dig through clay to set your concrete on bedrock, that would be ideal.
If you can, make a drawing and post it here. There are several generous engineers that frequent the site who will help you crunch numbers. I can't be bothered with math, I only have 10 fingers and usually it goes higher than that.
Suggestion for a gable design (one of many possible)- three piers, 10 feet out, one in the middle, one at each corner. Three beams, from posts atop the piers to the building. Rafters on the beams. Not the only, or necessarily the best, way to do it. This may require that you supplement or replace the piers on the house, because they may not be large enough for the new total load. For this type of calculation, if I use my fingers AND my toes I can almost do it, but my toenail fungus messes up my calculus
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